Continuous monitoring of respiratory events is an important clinical requirement as it serves detection of potential fatal physiological events such as acute respiratory failure and pulmonary diseases. Widely used existing methods employ contact sensors (spirometers) that are worn across the chest region of the patients which will produce a signal which is a function of the respiratory events. Such devices, albeit accurate, are associated with discomfort and psychological dependence. Furthermore, remote monitoring of respiratory events can aid applications in monitoring animals in a zoo, in a vet-spot or in situations such as monitoring infected subjects as in Ebola patients where contacts with subjects can lead to similar signs of illness in caretakers and contact tracing becomes extremely cumbersome.
Recently, there has been interest in estimation of respiratory patterns. Because methods based on color changes alone are known to be inaccurate during shallow breathing, 3D cameras (or depth sensors) have been utilized to detect subtle changes in respiratory volume by tracking movements in the chest-wall caused by the respiratory cycles. These methods are often considered superior to those which rely only on color-changes detected in light reflected from the surface as the subject breaths. This is because depth sensors exploit the 3D variations in the thoracic region caused by the respiratory cycles. In yet another method, a pre-specified patterned cloth is worn by the subject which is used to construct a sequence of 3D surface maps of the chest area to identify a respiratory pattern for the subject.
Accordingly, what is needed in this art are increasingly sophisticated systems and method for determining a subject's respiratory pattern from a video of that subject.